JPH09192846A - Spot welding equipment - Google Patents

Abstract

PROBLEM TO BE SOLVED: To continuously execute spot welding of a groove part of a work from the arbitrary direction with a platy welding tip. SOLUTION: Equipment is provided with pulleys 10, 11 to extension-drive a welding tip forming a platy part at its tip in the axial direction, a belt 18, a bearing 15 to support an arm 7 arranged with a welding tip around I axis, gears 12, 13, 14 or a clutch to selectively select one of the pulleys 10, 11 and a servo motor 4 connected to the clutch.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement of a spot welding apparatus for performing spot welding by superposing work pieces of plate-like members in a groove shape.

[0002]

2. Description of the Related Art In a vehicle such as an automobile, a body is composed of a plurality of outer plates joined by spot welding. Such a joint between the outer plates and the outer plate has been conventionally used. It is known that the step portions formed in the above are formed in a groove shape by superposing them on each other, and spot welding is performed in the groove portions to join them. Such spot welding is employed, for example, for joining a roof panel of a vehicle body and a body side panel (for example, a rear quarter panel forming a rear fender), and as shown in FIG. Steps 90A and 91 provided at the ends of the side 91, respectively
A is superposed on each other to form a groove 92 having a substantially rectangular cross section (cross section in the transverse direction of the groove).

The inner periphery and outer periphery (outside and inside of the vehicle body) of the bottom portion 92A of the groove portion 92 are sandwiched, pressed and energized by welding tips 5 and 6 supported by a gun unit (not shown) to perform welding. The welding tip 6 is supported by the gun unit via a “U” -shaped arm (not shown) or the like.

Since the groove portion 92 opens the concave portion toward the outside of the body, the inner peripheral width of the groove portion 92 in FIG. 6 is set to be narrow, for example, a groove having a narrow width such as 6 mm, so that the appearance of the vehicle body is improved. It is possible to secure the same and to eliminate a post-treatment step such as brazing.

The welding tip 5 inserted into the inner circumference of the groove 92 has a plate-like tip as shown in FIG. 7 in order to avoid contact with the inner peripheral side surface of the groove 92 other than the welding position. A tapered welding tip 5 is used.

The welding tip 5 has a base end supported on the gun unit side formed of a columnar member, and a plate-like portion 5A having a rectangular cross section is formed from the lower end of the columnar member. The plate thickness of the groove 5A is set to a value smaller than the width of the inner circumference of the groove 92, for example, 4 mm, and the groove 9 has a rectangular end surface.
Since the second bottom portion 92A is pressed and sandwiched and the side surface does not contact the inner circumference of the groove portion 92, spot welding can be smoothly performed at the groove-shaped welding position.

[0007]

By the way, there is a mixed flow line for treating a plurality of vehicle types or vehicle types in a vehicle body welding line, and it is necessary to weld a vehicle body having a different total roof length such as a three-door vehicle or a four-door vehicle. is there. Here, the groove portion 92 as described above is provided along the front-rear direction of the vehicle body at the side end portion of the roof panel 90 for joining the roof panel 90 and the side panel 91 as shown in FIG. Depending on the difference in the total length of the roof of a 3-door vehicle, a 4-door vehicle, etc., that is, the spot hitting position, the gun unit 2 is inserted in the rear opening 9A at the rear of the vehicle body or the side opening 9B at the side of the vehicle.
Etc. need to be changed appropriately.

However, the welding tip 5 as described above is used.
Is supported so that it can be displaced only in the axial direction.
In a four-door vehicle with a short roof length, as shown in FIG. 8, a "U" -shaped arm (not shown) of the gun unit 2 supporting the welding tip 6 below is inserted from the rear opening 9A at the rear of the vehicle body. Then, spot welding is performed from the rear to the front of the vehicle body at a predetermined interval. However, in a three-door vehicle with a long roof,
When the gun unit 2 is advanced forward, the arm of the welding tip 6 collides with the rear opening 9A. Therefore, a robot hand (not shown) is driven to pull out the gun unit 2'from the rear opening 9A once, It is necessary to insert the gun unit 2 again from the side opening 9B on one side to avoid the collision between the vehicle body 9 and the gun unit, but if the gun unit 2 is rotated 90 degrees in the horizontal plane as shown in 2'in the figure, Welding tip 5
However, there is a problem in that the plate-shaped tip portion is rotated in the direction crossing the groove portion 92 as indicated by 5'in the figure, and welding cannot be performed at the bottom portion 92A shown in FIG.

Therefore, the present invention has been made in view of the above problems, and provides a spot welding apparatus capable of performing spot welding in a narrow groove portion from an arbitrary direction with a welding tip having a plate-like tip. The purpose is to

[0010]

According to a first aspect of the present invention, there is provided a gun unit attached to a robot hand, and a plate-shaped portion attached to the gun unit and capable of inserting a tip into a groove-like work. No. 1 welding tip, an arm bent and attached to the gun unit so as to avoid contact with a work, and a second welding that faces the first welding tip coaxially and is supported by the arm. In a spot welding apparatus including a tip, at least one of the arm and the first welding tip is provided with a predetermined axial drive means for axially driving at least one of the first and second welding tips. And a drive means that rotates about the axis.

A second aspect of the present invention is a gun unit attached to a robot hand, and is attached to the gun unit so as to be supported so as to be displaceable in a predetermined axial direction, and the tip can be inserted into a groove-shaped work. A first welding tip formed of a flat plate-shaped portion, an arm bent to avoid contact with a work and attached to the gun unit, and the first welding tip facing the same coaxially with the first welding tip. In a spot welding apparatus provided with a second welding tip supported by an arm, an axial driving means for driving the first welding tip in an axial direction, and an arm rotatably supported around a predetermined axis. Arm support means and arm drive means for driving the arm are provided.

In a third aspect based on the second aspect, the axial drive means and the arm drive means are selectively supplied with power from one actuator via a switching means.

A fourth aspect of the present invention is a gun unit attached to a robot hand, which is attached to the gun unit and is supported so as to be displaceable in a predetermined axial direction, and the tip can be inserted into a groove-shaped work. A first welding tip formed of a flat plate-shaped portion, an arm bent to avoid contact with a work and attached to the gun unit, and the first welding tip facing the same coaxially with the first welding tip. In a spot welding apparatus provided with a second welding tip supported by an arm, an axial driving means for driving the first welding tip in an axial direction and the second welding tip can be rotated around an axis. And a rotation direction drive means for driving the rotation means.

In a fifth aspect based on the fourth aspect, the axial driving means and the rotational direction driving means of the first welding tip selectively drive power from one actuator via a switching means. Supplied.

[0015]

According to the first aspect of the present invention, the first and second welding tips face each other on the same axis, and the plate-shaped tip of the first welding tip is inserted into the groove-shaped work by the axial driving means, and at the same time, selective operation is performed. It is sandwiched and pressed to perform spot welding. Second
At least one of the arm and the first welding tip is bent to avoid the work while supporting the welding tip, and at least one of the arm and the first welding tip can be rotated around a predetermined axis by the driving means. When welding the groove, the arm is inserted through the opening on the rear side of the vehicle body and welded toward the front of the vehicle body.After the gun unit is pulled out before the arm contacts the roof, the arm or the By rotating one of the tips about a predetermined axis, the arm can be inserted into the vehicle from the side of the vehicle body while supporting the plate-shaped tip of the first welding tip along the groove. It is possible to smoothly weld the groove portions arranged in the front-rear direction.

According to a second aspect of the invention, the arm supporting the second welding tip can be rotated in any direction with respect to the direction in which the plate-shaped tip of the first welding tip is arranged by the arm supporting means. The axial driving means of the first welding tip clamps and presses the plate-shaped tip on the groove-shaped work to perform spot welding, and the arm driving means changes the direction of the arm according to the progress of welding. While maintaining the state in which the plate-shaped tip of the welding tip 1 is along the groove-shaped workpiece, the groove-shaped workpiece can be continuously spot-welded by changing the direction of the arm that avoids the workpiece.

According to a third aspect of the invention, the axial driving means for expanding and contracting the first welding tip and the arm driving means for rotating the arm are selectively supplied with power from one actuator via the switching means. Therefore, it is possible to prevent an increase in the number and mass of actuators arranged in the gun unit,
Prevents an increase in the load on the robot hand.

According to a fourth aspect of the present invention, the first welding tip can be displaced in the axial direction and around the axis by the axial driving means and the rotation direction driving means, and the plate-shaped tip of the first welding tip can be moved. The direction can be changed to any direction with respect to the arm attached to the gun unit, and the plate-shaped tip is clamped and pressed by the axial driving means of the first welding tip to press and work the grooved work. When the robot hand is driven to change the direction of the arm that avoids the work according to the progress of welding, the first rotation direction driving means is used.
By rotating the welding tip, the plate-shaped tip can be maintained in a state along the groove-shaped work, and spot welding can be continuously performed along the groove-shaped work.

According to the fifth aspect of the invention, the axial drive means and the rotational drive means of the first welding tip are selectively powered by one actuator via the switching means, so that the gun unit is attached to the gun unit. The increase in the number and mass of the actuators to be arranged is prevented, and the increase in the load on the robot hand is prevented.

[0020]

DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to the accompanying drawings.

FIGS. 1 and 2 show an example in which the present invention is applied to a spot welding device arranged on a welding line of a vehicle body.
Is a gun unit that is driven by the robot hand 1 to an arbitrary position and direction in a three-dimensional space. The work to be spot welded by the gun unit 2 is a roof panel 90 of the vehicle body 9 as shown in FIG. The case where joining is performed at the groove 92 at the end of the body side panel 91 is shown. The groove portion 92 of the vehicle body 9 is the groove portion 92 in which the ends of the roof panel 90 and the body side panel 91 are formed by bending, respectively, as in FIG. 6 of the conventional example, and as shown in FIG. Spot welding is performed by a welding tip 5 having a tip formed in a plate shape.

The gun unit 2 is mainly composed of a gun body 3 which is connected to the robot hand 1, and a welding tip 5 having a plate-like tip at the gun body 3 can be displaced in the axial direction as described later. Further, it is attached to the roof panel 90 of the vehicle body 9 so as to be opposed thereto.

A welding tip 6 fixed to the arm 7 is disposed at a position facing the welding tip 5 coaxially with each other.
Workpieces are clamped, pressed, and energized between the welding tips 5 and 6 that can be displaced in the axial direction. The welding tip 6 has a hemispherical tip portion, and the axis of the welding tips 5 and 6 is the I axis. 1 and 2, the I-axis is supported by the robot hand 1 so as to be parallel to the vertical direction of the vehicle body (Z-axis in the drawings). Hereinafter, the Y-axis in the drawings will be referred to as the vehicle front-rear direction, and the X-axis will also be used. Is the vehicle width direction.

The arm 7 for supporting the welding tip 6 disposed in the lower part of the drawing is formed in a substantially "U" shape in order to avoid contact with the work, and the base end of the arm 7 is a gun. It is connected to the body 3 and is supported rotatably around the I axis which is the axis of the welding tips 5 and 6.

The base end of the arm 7 is supported by the gun body 3 via a bearing 15, as shown in FIG.
Further, a gear 14 for driving the arm 7 around the I axis is fixedly provided at the base end.

On the other hand, as shown in FIG. 2, the welding tip 5 is supported by the gun body 3 through a shaft 50 which is displaceable in the I-axis direction, and the upper portion of the shaft 50 in the figure is rotatable coaxially. When the rotary shaft 16 is screwed, the shaft 50 is displaced in the I-axis direction according to the rotation of the rotary shaft 16, and the welding tip 5 is brought into contact with or separated from the work.

Here, a servo motor 4 for selectively driving the welding tip 5 and the arm 7 is fixedly mounted on the gun body 3.

The servomotor 4 is connected to a speed reducer 8. A pulley 10 and a gear 12 are attached to an output shaft 8A of the speed reducer 8 via a clutch 23, and the output shaft 8A has an I of welding tips 5 and 6. It is arranged parallel to the axis.

A pulley 11 is formed on a rotary shaft 16 screwed with a shaft 50 having the welding tip 5 attached thereto, and is connected to a pulley 10 provided on an output shaft 8A of the speed reducer 8 via a belt 18. It

Further, the gear 1 fixed to the base end of the arm 7
4 and the gear 12 of the output shaft 8A of the speed reducer 8 mesh with each other via a counter gear 13.

Here, the clutch 23 is the controller 3
According to a command from 0, one of the pulley 10 or the gear 12 and the output shaft 8A are selectively coupled, and the pulley 10 and the gear 12 are selectively engaged with one of them. Displacement regulating means 17 for stopping is provided.

The displacement restricting means 17 is composed of pins or the like that selectively join holes (not shown) formed in the pulley 10 and the gear 12, respectively.
Pulley 10 or gear 12 released from clutch 23
One of them is fixed to the gun body 3 side to selectively restrict the displacement of the welding tip 5 in the I-axis direction or the displacement of the arm 7 around the I-axis.

The gun unit 2 includes a rotary shaft 16
A rotary shaft encoder 21 for detecting the displacement of the arm 7 and an arm rotary encoder 2 for detecting the displacement of the arm 7 are provided,
The outputs of these encoders are input to the encoder that drives the servomotor 4.

Further, the gun body 3 is provided with a correction device 19 having a pin 19A that is displaceable in the axial direction. By engaging the pin 19A with the inner circumference of the groove portion 92, a machining error of the vehicle body 9 or the like is caused. Is absorbed and the side surface of the welding tip 5 is positioned so as not to contact the groove 92, and the gun unit 2 is guided so that only the end of the plate-shaped portion 5A and the bottom 92A of the groove 92 contact each other. . In addition, as such a correction device 19, Japanese Patent Application No. 7-9 proposed by the applicant of the present application is proposed.
It may have the same configuration as the No. 8710.

The welding tip 6 fixed to the arm 7
The energization to the side is performed by the wiring (not shown) accommodated in the flexible and extendable tube 20, and the welding tip 6 is electrically connected to the power supply means (not shown) regardless of the rotating position of the arm 7.

With the above construction, the operation will be described.

The controller 30 controls the robot arm 1, the servomotor 4, the clutch 23 and the displacement regulating means 17 to drive the gun unit 2 to a predetermined position on the vehicle body 9 and selectively select the arm 7 and the welding tip 5. By driving the welding tip 5 and the arm 7 by spot driving, the groove portion 92 of the vehicle body 9 is spot-welded.

When the welding tip 5 is driven in the I-axis direction in order to clamp, press or release the work, first,
The output shaft 8A of the speed reducer 8 is fastened to the pulley 10, the clutch 23 is driven to release the gear 12, and the gear 1
The displacement regulating means 17 is driven so as to lock 2.

When the servomotor 4 is driven, only the pulley 10 rotates and the rotary shaft 16 rotates via the belt 18 and the pulley 11, and the shaft 50 of the welding tip 5 screwed with the rotary shaft 16 is I. It expands and contracts in the axial direction.

The controller 30 is the rotary shaft encoder 2
The welding tip 5 can be extended or contracted to a predetermined position based on the output of No. 1, and the gear 12 is locked by the displacement restricting means 17 while the welding tip 5 is being expanded or contracted. The rotation position of can be held.

On the other hand, when the arm 7 is rotated, the output shaft 8A of the speed reducer 8 and the gear 12 are fastened, the clutch 23 is driven to release the pulley 10, and the pulley 1 is released.
The displacement regulating means 17 is driven so that 0 is locked.

Then, when the servomotor 4 is driven, only the gear 12 rotates and the arm 7 rotates via the counter gear 13 and the gear 14, and the controller 30 determines a predetermined value based on the output of the arm rotation encoder 22. The arm 7 can be rotated to the position, and the pulley 10 is locked by the displacement restricting means 17 while the arm 7 is rotationally driven, so that the welding tip 5 can maintain a predetermined axial position.

In this manner, the expansion and contraction of the welding tip 5 and the rotation of the arm 7 can be selectively performed by one servo motor 4, and the mass of the gun unit 2 attached to the robot hand 1 can be reduced. The rapid movement and positioning of the robot hand 1 can be promoted.

The welding of the roof panel 90 and the body side panel 91 by the gun unit 2 thus constructed is carried out as shown in FIG.

First, with the opening of the arm 7 facing the front of the vehicle body 9, the welding tip 5 faces the predetermined position of the groove portion 92 in which the roof panel 90 and the body side panel 91 are overlapped with each other. The robot hand 1 is driven so as to move the gun unit 2 to the rear opening 9A side that is opened rearward. The arm 7 is rotated in advance along the plate-shaped portion 5A of the welding tip 5.

At this time, the robot hand 1 is arranged so that the plate-shaped portion 5A of the welding tip 5 is aligned with the groove 92.
The welding tip 5 faces the opening side of the groove 92 while the arm 7 is inserted into the vehicle body 9 to bring the welding tip 6 into contact with the rear surface of the groove 92.

Here, as described above, the clutch 23,
The displacement regulating means 17 and the servo motor 4 are driven to extend the welding tip 5 in the I-axis direction, and the groove 92 is sandwiched and pressed between the welding tip 6 and the welding tip 6 on the back surface of the groove 92, and then power is supplied (not shown). Spot welding is performed by energizing by means.

Then, after the welding tip 5 is contracted and driven, the robot hand 1 is displaced along the groove 92 toward the front side of the vehicle body and driven to the next welding position, and spot welding is performed in the same manner as above.

In this manner, when spot welding is sequentially performed from the rear opening 9A toward the front of the vehicle body, the inner periphery of the arm 7 collides with the end of the roof panel 90. Then, the arm 7 is driven so as to be inserted into the side opening 9B opened laterally of the vehicle body 9.

At this time, by driving the servomotor 4 as described above, the arm 7 is rotated from the state along the front-rear direction of the vehicle body 9 to the position 7A in FIG. It is possible to smoothly perform spot welding to the end of the groove 92 by inserting the arm 7 from the side of the vehicle body 9 while maintaining the plate-shaped portion 5A of the tip 5 along the groove 92.

In this way, it becomes possible to solve the problems of the conventional example and smoothly perform spot welding by the welding tip 5 having the plate-shaped portion 5A in the mixed flow line for processing a plurality of vehicle types and vehicle types. , A single gun unit 2 can support multiple vehicle types, etc. By improving the operating rate of the welding robot composed of the robot hand 1 and the gun unit 2, productivity is improved and capital investment is reduced. Since the arm 7 and the welding tip 5 can be driven by one servo motor 4, the mass added to the robot hand 1 is prevented from being increased, and positioning is performed quickly and with high accuracy. Therefore, the takt time and the welding quality can be secured at the same time.

Although the arm 7 has an example in which the rotation axis is set on the I-axis coaxial with the welding tips 5 and 6, it is not shown in the figure, but if it is parallel to the I-axis, the arm 7 is rotated to any position. You can set the axis.

FIG. 4 shows a second embodiment in which the arm 7 is fixed to the gun body 3 while the welding tip 5 is displaceable in the I-axis direction and around the I-axis.

The shaft 50 supporting the welding tip 5 is
Similar to the first embodiment, the rotary shaft 16 (not shown) coupled to the pulley 11 is screwed to be driven in the I-axis direction, while being coupled to the sleeve 50A rotatable around the I-axis in the rotational direction. To do.

In the sleeve 50A, a gear 14A meshing with the counter gear 13 is provided instead of the gear 14 provided at the base end of the arm 7 of the first embodiment, and the clutch 2
The sleeve 50A is driven around the I-axis by the gear 12 that is selectively coupled to the output shaft 8A of the speed reducer 8 via 3 (not shown), and is fixed to the shaft 50 that is rotationally coupled to the sleeve 50A. The plate-shaped portion 5A of the welding tip 5 is I
It can be displaced to any position around the axis. The displacement of the welding tip 5 in the I-axis direction and around the I-axis depends on the first
Similar to the embodiment, it is selectively performed by the clutch 23, the displacement regulating means 17, and the servomotor 4.

Further, in place of the encoder 22 for detecting the rotation of the arm 7, a chip rotary encoder 22A for detecting the displacement of the shaft 50 around the I axis is provided, and the controller 30 (FIG. (Not shown)
Rotates the plate-shaped portion 5A around the I-axis based on the output of the chip rotary encoder 22A.

Welding of the roof panel 90 and the body side panel 91 by the gun unit 2 thus constructed is performed as shown in FIG.

First, the plate-like portion 5A of the welding tip 5 is preliminarily driven along the arm 7, and then the opening of the arm 7 is opened rearward of the vehicle body 9 with the opening thereof facing the front of the vehicle body 9. The robot hand 1 is driven so as to move the gun unit 2 to the rear opening 9A side, and spot welding is sequentially performed toward the front of the vehicle body as in the first embodiment.

When the gun unit 2 is displaced toward the front of the vehicle body and the inner circumference of the arm 7 approaches the end of the roof panel 90, the gun unit 2 is once pulled out to the rear of the vehicle body 9 and then the vehicle body 9 side. The arm 7 is driven so as to be inserted into the side opening 9B which is open toward one side.

At this time, the robot hand 1 rotates substantially 90 degrees so that the arm 7 extends along the vehicle width direction, the robot hand 1 moves to the position 1A in the figure along the vehicle width direction, and is fixed to the gun unit 2. The provided arm 7 also moves to the position 7A in the figure.

In this state, the plate-shaped portion 5A of the welding tip 5 is
Is orthogonal to the groove portion 92, the clutch 23, the displacement regulating means 17 and the servomotor 4 are driven in the same manner as in the first embodiment so that the welding tip 5 moves about 9 times around the I axis.
Rotate 0 degrees.

Thus, the arm 7 is inserted from the body side opening 9B into the back surface of the groove 92 so that the welding tip 6 abuts the back surface of the groove 92, while above the groove 92, the welding tip 5 moves the plate portion 5A into the groove. Opposite to each other along the disposition direction of 92, the robot hand 1 is moved in parallel to the front of the vehicle body 9 while driving the welding tip 5 to expand and contract in the I-axis direction. Similar to the embodiment, spot welding can be smoothly performed up to the front end of the groove portion 92, and like the first embodiment, one welding robot can handle a plurality of vehicle types and vehicle types. By improving the operation rate of the welding robot including the robot hand 1 and the gun unit 2, it is possible to improve productivity and reduce capital investment. Since the drive around the axis can be performed by one servo motor 4, it is possible to prevent an increase in the mass added to the robot hand 1, perform quick and highly accurate positioning, and secure takt time and welding quality at the same time. It is possible.

[0063]

As described above, according to the first aspect of the present invention, the first and second welding tips face each other on the same axis, and the plate-shaped tip of the first welding tip is grooved by the axial driving means. While inserting into the work and selectively sandwiching and pressing to perform spot welding, it supports the second welding tip and is bent to avoid the work, and at least one of the arm and the first welding tip is driven. Since it is possible to rotate about a predetermined axis by the means, for example, when welding a groove formed in the roof of the vehicle body, the arm is inserted from the opening at the rear of the vehicle body and the welding is performed toward the front of the vehicle body. , After pulling out the gun unit once before the arm contacts the roof, if one of the arm and the first tip is rotated around a predetermined axis, the plate-shaped tip of the first welding tip is set in the groove. It is possible to continuously weld the groove portions arranged in the front-rear direction of the vehicle body by inserting the arm into the vehicle from the side of the vehicle body while supporting it. This is not the case, and a single gun unit can handle multiple vehicle types and vehicle types, and it is possible to improve the operating rate of the welding robot and improve productivity.

According to the second aspect of the invention, the arm supporting the second welding tip can be rotated in any direction with respect to the direction in which the plate-shaped tip of the first welding tip is arranged by the arm supporting means. The axial driving means of the first welding tip clamps and presses the plate-shaped tip on the groove-shaped work to perform spot welding, and the arm driving means changes the direction of the arm according to the progress of welding. 1 While maintaining the state of the plate-shaped tip of the welding tip along the groove-shaped work, by changing the direction of the arm that avoids the workpiece, the groove-shaped work can be continuously spot-welded, Grooves arranged in the front-rear direction of the vehicle body can be welded continuously, and a single gun unit can be used for multiple vehicle types and vehicle types, improving the operating rate of the welding robot and producing. To improve Bet is to become possible.

According to a third aspect of the invention, the axial drive means for expanding and contracting the first welding tip and the arm drive means for rotating the arm are selectively powered by one actuator through the switching means. Therefore, it is possible to prevent an increase in the number and mass of actuators arranged in the gun unit,
It is possible to prevent the load on the robot hand from increasing,
The takt time and welding quality of the welding line can be secured by suppressing the deterioration of the positioning speed and accuracy of the robot hand.

According to a fourth aspect of the invention, the first welding tip can be displaced in the axial direction and around the axis by the axial driving means and the rotation direction driving means, and the plate-shaped tip of the first welding tip can be moved. The direction can be changed to any direction with respect to the arm attached to the gun unit, and the plate-shaped tip is clamped and pressed by the axial driving means of the first welding tip to press and work the grooved work. When the robot hand is driven to change the direction of the arm that avoids the work according to the progress of welding, the first rotation direction driving means is used.
By rotating the welding tip, the plate-shaped tip can be maintained along the groove-shaped work, and spot welding can be performed continuously along the groove-shaped work. The unit can support multiple vehicle types and vehicle types, and it is possible to improve the operating rate of the welding robot and improve the productivity.

Further, in the fifth aspect of the invention, the axial drive means and the rotational drive means of the first welding tip are selectively supplied with power from one actuator through the switching means, so that the gun unit is attached to the gun unit. It is possible to prevent an increase in the number and mass of actuators to be installed, to prevent an increase in the load on the robot hand, to control the positioning speed and accuracy of the robot hand, and to reduce the takt time and welding quality of the welding line. Can be secured.

[Brief description of the drawings]

FIG. 1 is a front view of a spot welding apparatus of the present invention.

FIG. 2 is a schematic perspective view of the same main part.

FIG. 3 is a schematic perspective view showing how the vehicle body is welded.

FIG. 4 is a front view of a spot welding apparatus showing a second embodiment.

FIG. 5 is a schematic perspective view showing how the vehicle body is welded.

FIG. 6 is a cross-sectional view of a vehicle roof panel and a body side at a welding position.

FIG. 7 shows a welding tip having a plate-shaped tip,
(A) is a plan view, (B) is a front view, and (C) is a side view.

FIG. 8 is a plan view showing a state of welding a roof panel and a body side of a conventional vehicle.

[Explanation of symbols]

 1 Robot Hand 2 Gun Unit 3 Gun Body 4 Servo Motor 5, 6 Welding Tip 5A Plate-shaped Part 7 Arm 8 Reducer 8A Output Shaft 9A Rear Opening 9B Side Opening 9 Car Body 10, 11 Pulley 12, 14 Gear 13 Counter Gear 15 bearing 16 rotary shaft 17 displacement restricting means 18 belt 19 correction device 20 cable 21 rotary shaft encoder 22 arm rotary encoder 22A chip rotary encoder 23 clutch 30 controller 50 shaft 50A sleeve 90 roof panel 91 body side panel 90A, 91A step portion 92 Groove 92A Bottom

Claims (5)

[Claims] 1. A contact between a work unit and a gun unit attached to a robot hand, a first welding tip formed of a plate-like portion attached to the gun unit and capable of inserting a tip into a groove-like work. An arm attached to the gun unit in a bent shape to avoid
In a spot welding device comprising a welding tip and a second welding tip that is coaxially confronted and supported by the arm, a shaft that drives at least one of the first and second welding tips in the axial direction. A spot welding apparatus comprising: direction driving means and driving means for rotating at least one of the arm and the first welding tip about a predetermined axis. 2. A gun unit attached to a robot hand, and a plate-shaped portion attached to the gun unit and supported so as to be displaceable in a predetermined axial direction and having a tip end which can be inserted into a groove-like work. The welded first welding tip, the arm bent to avoid contact with the work and attached to the gun unit, the first welding tip coaxially confronting the first welding tip and supported by the arm. In a spot welding apparatus provided with two welding tips, an axial driving means for axially driving the first welding tip, and an arm supporting means for supporting the arm rotatably around a predetermined axis, A spot welding apparatus comprising: arm driving means for driving an arm. 3. The spot welding apparatus according to claim 2, wherein the axial driving means and the arm driving means are selectively supplied with power from one actuator via a switching means. 4. A gun unit attached to a robot hand, and a plate-shaped portion attached to the gun unit and supported so as to be displaceable in a predetermined axial direction and having a tip end that can be inserted into a groove-like work. The welded first welding tip, the arm bent to avoid contact with the work and attached to the gun unit, the first welding tip coaxially confronting the first welding tip and supported by the arm. In a spot welding apparatus provided with two welding tips, an axial driving means for axially driving the first welding tip and a rotation means for supporting the second welding tip rotatably around an axis. And a rotating direction driving means for driving the rotating means, the spot welding apparatus. 5. The axial drive means and the rotational drive means of the first welding tip are selectively powered by one actuator via a switching means. Spot welding equipment.